shivatomix

And after deleting the plugin, orphaned tables and options still remain in the database…

Ah – ok, I thought the ultimate question is
“whats the sense of life? (42)” ??

In fact the main site is still in developement and it will take too long to wait until it’s finished.
So the main site should be not accessable temporarely.
Is it possible to add another if condition for the main site?
Sorry, I don’t know much about PHP.

Many thanks Ipstenu,

this works great for the subsites. I had to change
wp_redirect(network_home_url() );
to
wp_redirect('website.com') (my external url)

But what to do with the root-site / of “homepage.com”,
which I cannot delete, archive or deactivate?

Would be great if you have a solutions for the mainsite too.

Thanks a lot for your help, I really googled it like crazy ??

Thanks for your answers. Maybe I should describe the problem in another way.
First thing is, that I don’t like any messages to be displayed – it doesn’t look nice.

I want it like that: I have a site: “webpage.com” and I have the WP multisite installation under “homepage.com” with all that subsites installed.

If somebody tries to access “homepage.com” or one of the “hidden” subsites, f.e. homepage.com/subsite3″ he should be forwarded to “webpage.com”, which is installed on a totaly other server.

I can realize this with the Yoast-SEO-plugin, but only page by page.
And if possible, I don’t want to use a plugin.

Have you any ideas for me?
Thank you ??